Starting device for engines



Dec. 24, 1935. P. CIBIE STARTING DEVICE FOR ENGINES Filed June 9, 1954 2 Sheets-Sheet l NVVE/VTQQ 1 /52/25 (75/5 4 KM. A TTOEA/EKS Dean-24, 1935. P. CIBIE v EJ925195 STARTING DEVICE FOR ENGINES Filed June 9, 1934 2 Sheets-Sheet 2 Patented Dec. 24, 1935 UNITED STATES smear OFFlrCE Application June 9, 1934, Serial No. 729,865 In France June 22, 1933 3 Claims.

Starting devices for explosion motors which comprise the use of an electric motor carrying upon its shaft a system which when rotated automatically connects said motor with the hand wheel of the explosion motor by means of a pinion gearing with a crown gear integral with said hand wheel are well known.

The present invention has for its object a starting device of that kind which is notably simple in construction and occupies lengthwise a very small floor space.

According to a first mode of execution the present device is substantially characterized by the provision of a pinion integral with an unbalanced plate which is laterally provided with a portion of a screwthread which is engaged between the coils of a spring acting as a nut and rigidly connected at its front end with a cage keyed upon the shaft of the electric motor in which it is contained, said cage being provided with a front cover forming an abutment for said plate when the pinion is thoroughly engaged with the crown gear of the hand wheel.

According to another mode of construction a spring is interposed between the pinion and acage secured upon the shaft, one of its ends being made integrally with one of said elements, pinion or cage. and its other end being guided in a helical groove of the other element, cage or pinion.

The appended drawings show by way of example various modes of execution of a starting device according to the present invention.

Fig. l is a longitudinal vertical section of a first mode of construction.

Fig. 2 is a partly sectional view of same drawn along the line 2-2 in Fig. 1.

Fig. 3 is a longitudinal sectional view of a second form of execution, the pinion being in its position of engagement.

Fig. 4 is a transverse sectional view of same, drawn along the line 4444 in Fig. 3.

Fig. 5 is a developed plan view illustrating another form of groove.

In the first mode of execution shown in Figs.

1 and 2, upon the shaft I of the electric motor,

is keyed a kind of cage constituted by a cylindrical tubular part 2, a ring 2 forming a back cover, and a front cover 2 provided with an opening 3, which front cover may be formed by a flange of part 2.

A strong spring 4 having preferably a square or a rectangular section which is secured at 4 only upon the front cover 2 is contained said cage.

In the interior relatively to spring 4 a unit comprising an unbalanced plate 5 and a pinion 6 is slidingly mounted upon shaft I, said pinion is designed to engage the teeth I of the hand wheel of the motor to be started and can for this purpose pass through the opening 3.

The plate 5 is provided laterally with a projecting portion 8 shown by broken lines in Fig. 1, which has the shape of a screwthread and the side surfaces of which engage the adjacent surfaces of two coils of the spring 4.

When inoperative the unit 5-6 is inside the cage, the screwthread 8 is at 8 The electric motor being started its shaft I draws along rotatively the cage 22 --2 and the spring 4.

The plate 5 being unbalanced does not turn and likewise the pinion 6 remains stationary. Therefore said unit 5-45 is moved in parallel with the shaft I through the action of the thread of the spring nut 4 upon the screwthread 8.

If the teeth of the pinion 6 come in engagement with those of the crown gear I of the hand wheel, the motor being still in rotation, the coils of the spring nut 4 located at the back of the screwthreaded portion 8 move back, are compressed and exert upon said screwthreaded portion a pressure producing a tractive force which when it is stronger than the adherence between the teeth (friction) causes a rotation of the pin- 30 ion owing to which the teeth of the latter engage between those of the hand wheel under the sudden release of the spring 4.

The pinion being in engagement with the handwheel moves in parallel with the shaft I until the front side of the plate 5 abuts upon the cover 2 (Fig. 1).

The resisting torque of the motor must then be overcome. The plate 5 integral with the pinion 6 slides upon the cover 2 and the screwthread element 8 upon the spring nut 4 which again moves back and bends up to the moment when the pressure of plate 5 upon the cover 2 and of spring 4 upon the screwthread 8 causes an adherence which is strong enough to rotate the pinion and to overcome the motor torque.

Until the moment when the plate 6 has engaged the cover 2 the work required from the electric motor was equal to zero. Consequently through the intermediary of the spring, the power necessary to overcome the resisting torque has been progressively applied to all the members of the device.

When the electric motor is stopped the 7 4 drawing along the unit 5-5 which re-enters the cage.

According to a second mode of execution illustrated in Figs. 3 and 4, the shaft ll of the starting electric motor carries a cylindrical cage [2 provided with an helical groove I3 having an appropriate pitch and length, inwhich a feather M is engaged and guided. The latter is formed by the bent up end of a spring [4 having oneor several coils and hooked at its other end to a ring l5 surrounded by said spring. 7

The ring I5 is integral with a sleeve l6 free upon shaft H which carries at its opposite end the driving pinion ll.

In order to ensure a good driving of the ring H: by the spring, it is necessary that it should be strongly secured upon same. Accordingly the end of the spring embodied in the ring may be 7 locked by means of a screw I8 and a boss or a grooved screw head IS in which the spring passes may be provided near said end of the spring.

The working is as follows:

The motor being started its shaft draws the cage l2 rotatively. The unit l5, l6, H by reason of its inertia does not rotate, it consequently moves in parallel with the shaft under the action of the cage groove l3 'upon the spring M which is integral with said unit.

When the pinion teeth engage the teeth of the V crown gear upon the hand wheel 20, as the motor continues to rotate the shape of the spring alters as it takes up the thrust of the pinion and unbends suddenly when the teeth come in engagement. The pinion being in engagement with the hand wheel still continues to move in parallel with the shaft up to the moment when the spring drawn along by the bottom of the groove in the cage will progressively be bent as it tightens around the ring and will cause it and the pinion to rotate.

7 Up to the moment when the spring engages the bottom of the cage groove, the work required from the electric motor was equal to zero. Consequently by the intermediary of the spring the power required to overcome the resisting torque .has been progressively applied upon all the elements of the device.

. According to another mode of construction the spring could be attached to the pinion and arranged outside the cage its inwardly bent end entering then from outside in the groove provided in the cage or in any other part carried upon the shaft.

' According to a modified form of execution of the devices illustrated in Figs. 3 and 4, the groove l3 instead of being of helical shape has the shape shown in Fig. 5.

The straight portion A is designed to prevent the displacement of the pinion due to itsoscillatory movements caused by vibrations, so that when working normally its teeth cannot come in engagement with those upon the hand wheel.

The slope B is slightly inclined in order that the pinion and its auxiliary parts which have a low inertia may move without rotating along the distance which divides it from the crown gear until it slightly engages same. This arrangement reduces the shocks upon the teeth.

The incline of the slope C is the greatest possible for allowing the feather M to slide and the pinion to move forward,'the rotation of the latter being prevented owing to its engagement with the handwheel teeth. The rotation takes place when the bottom 0 of the part C draws the feather in the same manner as above described, the

pinion being then thoroughly engaged.

The present device allows of obtaining the required displacement of the pinion with a very small angle of rotation of the cage l2 and of the motor. The larger the cage the smaller said angle will be.

In an existim apparatus said angle of rotation is of 82 approximately. 7

The advantage of the present arrangementis to reduce the kinetic energy of the motor system and of the damping system, to annihilate the shocks and consequently to increase the life of the parts.

What I claim and desire to secure Patent of the United States is:

1. In a starting device comprising a starting motor designed to drive a crown gear integral with the motor to be started, a cage secured upon the starting motor shaft, a pinion loosely carried upon said shaft for gearing with said crown gear, a spring secured at one end to one of said two elements and bent up at its other end in order to form a feather to engage in a groove in the other element, the bottom of said groove being so located as to cause the pinion to be rotatively driven when it is thoroughly engaged with the crown gear.

2. In a starting device comprising a starting motor designed to drive a crown gear integral with the motor to be started: a cage secured upon the shaft of the'starting motor and provided with a groove in its cylindrical wall, a pinion loose upon said shaft to engage with the crown gear; a spring secured at one end upon said pinion and bent up at its other end so as to form a feather engaged in the groove of the above mentioned cage, the bottom of said groove being located so as to rotatively drive the spring when the pinion is thoroughly engaged with the crown gear.

3. A starting device according to claim 2, characterized in that the groove in the cylindrical cage comprises a portion normal to the generatrix in which the feather of the spring is engaged when inoperative, said portion being extended by a slightly inclined portion of predetermined length to cause the forward movement of the spring and of the pinion up to the point where the latter is slightly engaged in the crown gear, and lastly a portion of much greater obliquity designed to cause the rectilinear movement through which the pinion is made'to engage thoroughly with the crown gear.

by Letters PIERRE CIBIE. 

